The OTT is set in msec in the configuration and is not 2500ms either(default of 1000) so not sure where it is deriving this from. As a quick test I tried forcing a pass on the section that makes this evaluation at line 207 in data.c and it just seg faults instead now. It crashes with the aforementioned log message without the modification.

Both the probes have the same time source, one of them has the MySQL daemon on them(10.0.0.30) and here is what the configuration looks like: